The technical scope of the present invention is that of priming devices for the explosive charge of a sub-munition onboard a carrier, for example a rocket. These sub-munitions are, classically, stacked on several columns inside the carrier, then scattered in great number over the target.
The priming devices for sub-munitions scattered by a carrier must satisfy safety conditions during the phases of storage and handling before their use.
After firing, in the event of the non-functioning of the main priming device of the charge, secondary self-destruction means are generally controlled to avoid polluting the field with live, and therefore hazardous, sub-munitions.
A simple and economical way to create self-destruction means is to implement a delay composition ignited by a firing pin.
Patent FR2650662 describes such means in which a self-destruction firing pin is integral with the primer slide. The disadvantage of these means lies in that if the primer slide is blocked, self-destruction is not activated. Patent FR2737293 also describes a priming device for an on-board sub-munition notably comprising a firing pin, primer, means to lock the primer and self-destruction means.
The self-destruction means comprise a pivoting cam armed by a spring and carrying a firing pin. This cam is held in the safety position by a lock formed by a finger integral with a primer drum.
Once again, the primer holds the self-destruction means in place. If for any reason the primer drum does not pivot, self-destruction is not triggered.
Moreover, the cam exerts constant force on the primer drum. This may result in sticking after long storage periods. This may in turn disturb the passage of the primer into its armed position.